JP2008032765A - Paper ejection device and image forming apparatus - Google Patents

Paper ejection device and image forming apparatus Download PDF

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Publication number
JP2008032765A
JP2008032765A JP2006202757A JP2006202757A JP2008032765A JP 2008032765 A JP2008032765 A JP 2008032765A JP 2006202757 A JP2006202757 A JP 2006202757A JP 2006202757 A JP2006202757 A JP 2006202757A JP 2008032765 A JP2008032765 A JP 2008032765A
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Prior art keywords
paper
paper discharge
air
air blowing
sheet
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JP2006202757A
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JP4862531B2 (en
Inventor
Hiroaki Fujikura
Hiroshi Iwasaka
Michio Tada
Yoichi Yamakawa
通夫 多田
洋一 山川
啓 岩坂
寛明 藤倉
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Fuji Xerox Co Ltd
富士ゼロックス株式会社
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Abstract

An object of the present invention is to effectively prevent a paper sticking phenomenon due to adhesiveness (softening) of a developer when discharging a paper on which an image is fixed.
An image forming apparatus according to the present invention includes a paper discharge roll 24 for discharging paper on which an image is formed, a paper stacking plate 25 for storing paper 27 discharged by the paper discharge roll 24 in a stacked state, and paper stacking. A blower 31 that blows air to the end of the paper 27 loaded on the plate 25 through the blower opening and a blower opening / closing mechanism 31 that opens and closes the blower opening in the paper stacking direction are provided.
[Selection] Figure 3

Description

  The present invention relates to a paper discharge device and an image forming apparatus.

  In an electrophotographic image forming apparatus, a sheet on which a toner image has been transferred by an image transfer unit is passed through an image fixing unit, and heat and pressure are applied to the sheet, thereby fixing the toner on the sheet. For this reason, the sheet that has passed through the image fixing unit is conveyed with heat. As a result, when the paper fed from the image fixing unit is discharged to the paper discharge device, the heated paper is successively stacked and discharged, so that heat is accumulated in the paper stacking portion of the paper discharge device. Go.

  Therefore, when a large amount of paper is discharged continuously, the toner on the paper is softened by heat, and the weight of the stacked paper is added to the discharged paper so that the papers are in close contact with each other. It becomes a state. As a result, there occurs a phenomenon (blocking phenomenon) in which sheets discharged on the sheet stacking unit are stuck to each other due to the softness of the softened toner.

  Therefore, Patent Document 1 discloses a technique for cooling a sheet after image fixing with a heat pipe. Patent Document 2 discloses a technique for blowing and cooling a sheet on the downstream side of the image fixing unit, and Patent Document 3 discloses a technique for cooling the sheet by a cooling roll on the downstream side of the image fixing unit. Has been. Japanese Patent Application Laid-Open No. H10-260260 discloses a technique for cooling a sheet fed from an image fixing unit and folded and stacked on a table by blowing air.

JP-A-4-260065 Japanese Patent Laid-Open No. 9-22228 Japanese Patent Laid-Open No. 10-69134 JP 2000-302325 A

  The present invention provides a paper discharge device and an image forming apparatus capable of effectively preventing a paper sticking phenomenon due to adhesiveness (softening) of a developer when a paper on which an image is fixed is discharged. Objective.

  According to the first aspect of the present invention, there is provided a sheet stacking unit that stores discharged sheets in a stacked state, a blower unit that blows air to an end portion of the sheet stacked on the sheet stacking unit through a blowing port, and the blowing port And a blower opening / closing means for opening / closing the paper in the paper stacking direction.

  According to a second aspect of the present invention, in the paper discharge device according to the first aspect, the maximum height of the paper that is levitated by the blowing of air from the blowing unit is regulated at a position lower than the paper discharge height. Means are provided.

  According to a third aspect of the present invention, in the paper discharge device according to the first aspect, a plurality of the air blowing means are provided at different positions in the paper discharge direction, and the plurality of air blowers are arranged according to the length of the paper to be discharged. The means is selectively operated.

  According to a fourth aspect of the present invention, in the paper discharge device according to the first aspect, there is provided means for controlling the start timing of the air blowing operation of the air blowing means based on the number of paper discharged from the start of paper discharge or the elapsed time. It is characterized by.

  According to a fifth aspect of the present invention, in the paper discharge device according to the first aspect, there is provided means for variably controlling the start timing of the air blowing operation of the air blowing means in accordance with the type of paper. .

  According to a sixth aspect of the present invention, in the paper discharge device according to the first aspect, the apparatus further comprises means for variably controlling the air blowing amount of the air blowing means according to the type of paper.

  According to a seventh aspect of the present invention, there is provided an image forming unit that forms an image on a sheet, a sheet discharging unit that discharges the sheet on which an image is formed by the image forming unit, and a stacking state of the sheet discharged by the sheet discharging unit A paper stacking means for storing in the paper stacking means, a blower means for blowing air to the end of the paper loaded on the paper stacking means through a blower opening, and a blower opening / closing means for opening and closing the blower opening in the paper stacking direction. An image forming apparatus characterized by the above.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect, whether or not to operate the blowing unit and the blowing port opening / closing unit according to image information formed on the sheet by the image forming unit. Is characterized by switching.

  According to the first aspect of the present invention, air is blown from the blowing unit by blowing air to the end of the paper loaded on the paper stacking unit through the blowing port and opening and closing the blowing port in the sheet stacking direction. Can easily enter between sheets. For this reason, the sheet can be floated in a state where an air layer is reliably formed between the sheets. Therefore, it is possible to efficiently cool the sheet that is levitated by blowing air. Further, the adhesion force acting between the sheets can be weakened by the floating of the sheets. As a result, it is possible to realize a paper discharge device that can effectively prevent the paper sticking phenomenon due to the adhesiveness (softening) of the developer when the paper on which the image is fixed is discharged.

  According to the second aspect of the present invention, the maximum height of the sheet floated by blowing the air from the air blowing means can be restricted so as not to obstruct the discharge of the sheet.

  According to the third aspect of the present invention, it is possible to control the necessary air blowing means to operate and the unnecessary air blowing means not to operate according to the length of the discharged paper.

  According to the fourth aspect of the present invention, since the sticking of the sheet is unlikely to occur while the number of sheets stacked on the sheet stacking unit is small due to the start of paper discharge, an unnecessary air blowing operation in such a situation Can be avoided.

  According to the fifth aspect of the present invention, when discharging a type of paper that is likely to stick, discharge the type of paper that is less likely to stick, by relatively increasing the start timing of the blowing operation. When doing, the start timing of air blowing operation can be relatively delayed.

  According to the invention described in claim 6, since the paper having a large basis weight (thick paper) is difficult to float, and the paper having a small basis weight (plain paper, thin paper) is easily floated, In addition, the air volume of the blowing means can be controlled appropriately.

  According to the seventh aspect of the present invention, when the paper on which the image is formed by the image forming unit is discharged by the paper discharging unit, air is blown through the air blowing port to the end of the paper stacked on the paper stacking unit, and By opening and closing the air blowing port in the paper stacking direction, the air blown from the air blowing means can easily enter between the papers. For this reason, the sheet can be floated in a state where an air layer is reliably formed between the sheets. Therefore, it is possible to efficiently cool the sheet that is levitated by blowing air. Further, the adhesion force acting between the sheets can be weakened by the floating of the sheets. As a result, it is possible to realize an image forming apparatus that can effectively prevent the sheet sticking phenomenon due to the adhesiveness (softening) of the developer when the sheet on which the image is fixed is discharged.

  According to the eighth aspect of the present invention, as the image information formed on the paper, for example, if the amount of toner used for image formation is an amount that does not cause the paper to stick, By performing the paper discharge process without operating the blower opening / closing means, power consumption can be reduced.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1 includes an image forming apparatus main body 2 and a paper discharge device 3. In the image forming apparatus main body 2, two sheet feeding apparatuses 4 and 5 are incorporated in two upper and lower stages. Each of the paper feeding devices 4 and 5 is configured using, for example, a paper storage unit having a tray shape, a cassette shape, a box shape, and the like, and a paper supply roll for feeding paper from the paper storage unit. It is.

  Further, the image forming apparatus main body 2 is formed with a sheet conveyance path for conveying sheets fed from the respective sheet feeding apparatuses 4 and 5. The paper transport path is formed by a transport path forming member (not shown). On the paper conveyance path, a plurality of conveyance rolls (roll pairs) 6 to 21 are provided at predetermined intervals.

  An image transfer device 22 and an image fixing device 23 are provided between the transport roll 10 and the transport roll 11 on the paper transport path. The image transfer device 22 transfers an image (toner image) onto a sheet conveyed along a sheet conveyance path. The image transfer device 22 includes a photosensitive drum 22A and a transfer roll 22B that are opposed to each other via a paper conveyance path. Although not shown, the image transfer device 22 exposes and scans the surface of the charger 22A charged to the photosensitive drum 22A and the photosensitive drum 22A charged to a predetermined potential by the charger with laser light. An image writing device for writing an electrostatic latent image and a developing device for developing the electrostatic latent image written by the image writing device using, for example, a two-component developer composed of toner and a carrier.

  The photosensitive drum 22A and the transfer roll 22B are arranged in contact with each other with a predetermined pressure. The photosensitive drum 22A rotates at a constant speed in the counterclockwise direction in the figure when an image is formed on a sheet. The transfer roll 22B rotates following the photosensitive drum 22A, sandwiches a sheet with the photosensitive drum 22A, and applies a charge having a polarity opposite to that of the toner to the sheet. The toner image is transferred onto a sheet.

  The image fixing device 23 fixes an image (toner image) on a sheet conveyed along a sheet conveyance path. The image fixing device 23 includes a heating roll 23A that is heated to a predetermined temperature (fixing temperature) by a heater or the like, and a pressure roll 23B that contacts the heating roll 23A with a predetermined pressure.

  The paper discharge device 3 includes a paper discharge roll (roll pair) 24 and a paper stacking plate 25. The discharge roll 24 is composed of a pair of rolls, one of which is a drive roll and the other is a driven roll. A plurality of discharge rolls 24 are provided side by side at a predetermined interval in a direction (depth direction in FIG. 1) perpendicular to the paper discharge direction. The discharge roll 24 receives a sheet on which an image has been formed in the image forming apparatus main body 2 from the transport roll 13 and discharges the sheet into the main body (hereinafter, “paper discharge apparatus main body”) 26 of the paper discharge apparatus 3. The paper stacking plate 25 accommodates the paper discharged by the paper discharge roll 24 in a stacked state. The paper stacking plate 25 is provided in the paper discharge apparatus main body 26 so as to be lifted and lowered.

  In the image forming apparatus 1 configured as described above, a sheet fed from one of the sheet feeding devices 4 and 5 is sent to the transport roll 10 according to the rotation of the transport rolls 6, 7, 8, and 9. Next, the sheet is fed into the image transfer device 22 according to the rotation of the transport roll 10. In the image transfer device 22, the toner image is transferred to the first surface of the paper when passing between the photosensitive drum 22 </ b> A and the transfer roll 22 </ b> B.

  Next, the sheet is sent to the image fixing device 23. In the image fixing device 23, the toner image is fixed on the first surface of the paper when passing between the heating roll 23A and the pressure roll 23B. Next, the paper is sent to the transport roll 13 according to the rotation of the transport rolls 11, 12, and further sent to the paper discharge roll 24 according to the rotation of the transport roll 13. Then, the paper is discharged from the image forming apparatus main body 2 to the paper discharge apparatus main body 26 according to the rotation of the paper discharge roll 24. The above operation is the case of single-sided image forming processing for forming an image on one side of a sheet.

  In the case of double-sided image forming processing in which images are formed on both sides of the paper, the paper that has passed through the image fixing device 13 is sent to the transport rolls 14, 15, 16 according to the rotation of the discharge rolls 11, 12. Then, when the trailing edge of the sheet passes between the conveyance roll 14 and the conveyance roll 15 through the branch position of the sheet conveyance path toward the conveyance roll 17 side, after the rotation of the conveyance rolls 15 and 16 is temporarily stopped, until then The transport rolls 15 and 16 rotate in the opposite direction. As a result, the sheet is fed into the transport roll 17.

  Thereafter, the sheet is fed again to the transport roll 8 according to the rotation of the transport rolls 17 to 21. Thereafter, an image is formed (transferred and fixed) on the second surface of the sheet in the same procedure as that for forming an image on the first surface.

  The paper on which images are formed on both sides in this way is sent to the paper discharge roll 24 through the transport rolls 11, 12, and 13 in order. Further, when the paper is turned upside down and discharged, the paper is fed to the transport rolls 14, 15, 16 according to the rotation of the transport rolls 11, 12, and then the paper is rotated by the reverse rotation of the transport rolls 14, 15, 16. Is fed to the transport roll 13.

  FIG. 2 is a plan view showing an internal configuration example of the paper discharge device 3. FIG. 3 is a view taken in the direction of arrow C in FIG. 2, and FIG. 4 is a view taken in the direction of arrow D in FIG. A pair of side guides 28 and 29 and an end guide 30 for guiding (regulating) the accommodation position of the paper 27 loaded on the paper stacking plate 25 are provided inside the paper discharge device main body 26. The side guide 28 is for aligning one side end position of the paper, and the side guide 29 is for aligning the other side end position of the paper. The end guide 30 is for aligning the end positions of the sheets.

  The side edge position of the paper refers to the position of the paper edge arranged in the direction orthogonal to the moving direction of the paper discharged by the paper discharge roll 24 (hereinafter also referred to as “discharge direction”). The end position of the sheet refers to the position of the end of the sheet that is arranged facing the downstream side in the moving direction of the sheet discharged by the discharge roll 24.

  The side guide 28 is provided in a fixed state on the paper discharge device main body 26. The side guide 29 is in a direction approaching and separating from the side guide 28 (a direction perpendicular to the paper discharge direction) so that the guide position can be adjusted automatically or manually according to the width of the paper discharged to the paper discharge device 3. It is provided to be movable. The end guide 30 is provided to be movable in the paper discharge direction so that the guide position can be adjusted automatically or manually according to the length of the paper discharged to the paper discharge device 3.

  The paper width refers to the paper size in the direction orthogonal to the paper discharge direction. The paper length refers to the paper size in the paper discharge direction.

  Two air blowers 31 are attached to the fixed side guide 28. The two air blowers 31 are arranged at the same position in the paper stacking direction (vertical direction). The two blowers 31 are arranged separately on the upstream side (side closer to the paper discharge roll 24) and the downstream side (side far from the paper discharge roll 24) with a predetermined interval in the paper discharge direction. Thus, they are provided at different positions in the paper discharge direction.

  Each air blower 31 sends air horizontally from one side guide 28 toward the other side guide 29. For this reason, a square air outlet 32 is formed in the side guide 28 corresponding to the attachment part of each air blower 31. Each blower 31 is attached to a portion where the blower opening 32 is formed via a blower opening / closing mechanism 33. The air outlet opening / closing mechanism 33 opens and closes the air outlet 32 of the side guide 28 in the paper stacking direction.

  One side guide 28 is provided with three claws 34, and the other side guide 29 is provided with two claws 34. These claws 34 regulate the maximum height of the sheet that is levitated by air blowing described later. The claws 34 are arranged at the same position in the sheet stacking direction (vertical direction). If the position where the pair of rolls constituting the paper discharge roll 24 sandwich the paper is defined as “paper discharge height”, each claw 34 is positioned at a position lower than the paper discharge height, and It regulates the maximum height.

  Each nail | claw 34 is provided in the state which protrudes from the surface (inner side surface of the side guides 28 and 29) which the side guides 28 and 29 oppose. In one side guide 28, three claws 34 are disposed so as to sandwich the air blowing port 32 in the paper discharge direction, and in the other side guide 29, 2 is provided with a predetermined interval in the paper discharge direction. Two nails 34 are arranged. Each claw 34 has a position protruding from the inner surface of each side guide 28, 29, as shown in FIG. 5A, and each side guide 28, 29, as shown in FIG. 5B. It can be selectively placed at a position retracted from the inner surface. Each claw 34 is movable between a protruding position shown in FIG. 5A and a retracted position shown in FIG. 5B by driving a motor, a solenoid, etc. (not shown).

  FIG. 6 is a schematic diagram showing a configuration example of the blower opening / closing mechanism. As shown in the figure, the air opening / closing mechanism 33 is configured by using a square frame member 35 corresponding to the opening shape of the air blowing port 32 and a shutter member 36 movably supported by the frame member 35. The shutter member 36 opens and closes the air blowing port 32 by reciprocating (up and down movement) in the paper stacking direction using a motor or the like (not shown) as a drive source. The shutter member 36 moves up and down to close the air blowing port 32 by moving upward (shutter raising operation) and to open the air blowing port 32 by moving downward (shutter lowering operation).

  Therefore, when the shutter member 36 is moved downward from a state where the air blowing port 32 is completely closed by the shutter member 36 (fully closed state), the air blowing port 32 gradually opens from the upper end side as the shutter member 36 moves. Go. Further, when the shutter member 36 is moved upward from the state in which the air blowing port 32 is fully opened by the shutter member 36, the air blowing port 32 is gradually closed from the lower end side as the shutter member 36 moves.

  FIG. 7 is a block diagram illustrating a configuration example of a control system that controls the operation of the paper discharge device 3. The paper discharge control unit 37 controls the rotation operation of the paper discharge roll 24, the lifting / lowering operation of the paper stacking plate 25, the air blowing operation of the blower 31, the retracting operation of the claw 34, and the opening / closing operation of the air outlet opening / closing mechanism 33. is there. For this reason, the paper discharge control unit 37 is connected with a paper discharge drive unit 38, a lift drive unit 39, a blower drive unit 40, a retreat drive unit 41, and an opening / closing drive unit 42 as targets of operation control.

  The paper discharge drive unit 38 is a drive source for rotating the paper discharge roll 24. The elevation drive unit 39 is a drive source for raising and lowering the sheet stacking plate 25. The blower drive unit 40 is a drive source for rotating a fan or the like by the blower 31. The retract drive unit 41 is a drive source for retracting the claw 34. The opening / closing drive unit 42 serves as a drive source for moving the shutter member 36 up and down in order to open and close the air blowing port 32 by the air blowing opening / closing mechanism 33.

  In addition, a paper discharge detection sensor 43 and a shutter open / close sensor 44 are connected to the paper discharge control unit 37. The paper discharge detection sensor 43 detects whether or not the paper discharge roll 24 is discharging paper. The paper discharge detection sensor 43 is disposed, for example, on the downstream side in the vicinity of the paper discharge roll 24. The shutter opening / closing sensor 44 detects the opening / closing state of the shutter member 36 in the air outlet opening / closing mechanism 33.

  FIG. 8 is a flowchart illustrating a procedure of a paper discharge process executed by the paper discharge control unit 37 when the paper on which the image is formed in the image forming apparatus main body 2 of the image forming apparatus 1 is discharged to the paper discharge device 3.

  First, the paper discharge control unit 37 drives the lift drive unit 39 to move the paper stacking plate 25 to the initial position (step S1), and then drives the retraction drive unit 41 to move the claw 34 from the protruding position to the retraction position. (Step S2). The initial position of the paper stacking plate 25 is set, for example, at a position where the upper surface (paper stacking surface) of the paper stacking plate 25 is the same as or lower than the lower end of the air blowing port 32.

  Next, the paper discharge control unit 37 drives the paper discharge driving unit 38 to start discharge of the paper by the paper discharge roll 24 (step S3). At this time, from the image information (for example, image density) formed on the sheet by the image forming apparatus main body 2, for example, the amount of toner used for image formation exceeds a preset predetermined use amount Operates the blower device 31 and the blower opening / closing mechanism 33 as will be described later in the processing after step S3, and when the toner usage amount is equal to or less than the predetermined usage amount, the blower device 31 and the blower opening port in the processing after step S3. The opening / closing mechanism 33 may be switched so as not to operate.

  Next, the discharge control unit 37 drives the retracting drive unit 41 to move the claw 34 from the retracted position when the number of sheets discharged by the discharge roll 24 (the number of discharged sheets) becomes n or more. Move to the protruding position (steps S4, S5).

  Next, the paper discharge control unit 37 drives the air blowing drive unit 40 to start the air blowing operation by the air blowing device 31, and drives the opening / closing driving unit 42 to start the shutter opening / closing operation by the air outlet opening / closing mechanism 33 ( Step S6).

  In starting the air blowing operation, the two air blowers 31 are selectively operated according to the length of the paper discharged by the paper discharge roll 24. Specifically, as shown in FIG. 9, when the length of the paper is shorter than a predetermined length, only the upstream air blower 31 is driven, and as shown in FIG. When longer than a predetermined length, the two air blowers 31 are driven together (simultaneously).

  Further, the value n of the number of discharged sheets may be changed according to the type (for example, size, thickness, etc.) of the sheet discharged by the sheet discharge roll 24. In this case, it is possible to variably control the start timing of the air blowing operation and the shutter opening / closing operation according to the type of paper. Further, the value n of the number of discharged sheets may be changed according to image information (for example, image density) formed on the sheet by the image forming apparatus main body 2. In this case, it is possible to variably control the start timing of the air blowing operation and the shutter opening / closing operation according to the image information. Further, instead of the step of determining whether or not the number of discharged sheets has reached n or more, a step of determining whether or not a predetermined time has elapsed since the start of sheet discharge may be applied. In this case, it is possible to control the start timing of the air blowing operation and the shutter opening / closing operation based on the elapsed time from the start of paper discharge. If the predetermined time is changed according to the paper type or image information, the start timing of the air blowing operation and the shutter opening / closing operation can be variably controlled according to the paper type or image information.

  The shutter opening / closing operation is performed by repeatedly moving the shutter member 36 up and down in a predetermined pattern by driving the opening / closing drive unit 42. 10A to 10D show the shutter opening / closing operation. The shutter member 36 gradually moved downward as shown in FIGS. 10B and 10C from the state where the air outlet 32 is completely closed (fully closed state) as shown in FIG. 10A. After that, as shown in FIG. 10D, the blower port 32 stops at a position where it is fully opened. Thereafter, the shutter member 36 gradually moves upward from a state where the air blowing port 32 is fully opened, and then stops at a position where the air blowing port 32 is completely closed. With this as one opening / closing cycle, the shutter member 36 repeats up and down movement.

  At this time, if the shutter member 36 is moved downward by driving the opening / closing drive unit 42 from a state in which the air blowing port 32 is completely closed by the shutter member 36, the air blowing port 32 gradually opens as the shutter member 36 moves. Then, the air sent out from the blower 31 flows through the blower port 32 to the paper stacking area side. For this reason, in the process in which the shutter member 36 moves downward, the air blowing area gradually expands downward. Therefore, air is blown sequentially from the upper layer to the end of the paper 27 loaded on the paper stacking plate 25. Further, in a state where the blower opening 32 is fully opened, the sheets 27 stacked on the sheet stacking plate 25 are floated in a form separated one by one by blowing air from the blower 31.

  At this time, as shown in FIG. 11, the maximum floating height of the paper 27 in the floating state is such that each claw 34 comes into contact with the uppermost surface of the floating paper 27, so that the floating height of the paper 27 is It is regulated (restricted) by being pressed by the claw 34. In this state, since the paper 27 does not float above the claw 34, the paper 27 floated by blowing air does not interfere with the paper discharge operation by the paper discharge roll 24.

  On the other hand, when the shutter member 36 is moved upward by driving the opening / closing drive unit 42 from the state in which the air blowing port 32 is fully opened by the shutter member 36, the air blowing port 32 is gradually closed as the shutter member 36 moves. The air sent out from the device 31 is blocked by the shutter member 36. For this reason, in the process in which the shutter member 36 moves upward, the air blowing area gradually shrinks upward, so that the paper 27 that has floated from the paper stacking plate 25 loses lift due to the air blowing and falls. . Further, when the blower port 32 is completely closed, the sheet 27 is loaded on the sheet stacking plate 25.

  Here, when the paper discharge control unit 37 drives the air blowing drive unit 40 to operate the air blowing device 31, the air blowing amount of the air blowing device 31 may be controlled to change according to the type of paper. For example, if the type of paper is thick paper having a large basis weight, a control form such as increasing the air volume of the blower 31 is employed as compared to plain paper.

  Further, in general, when an image is formed on thick paper by an image forming apparatus, productivity of image formation is low (the number of discharged sheets per unit time is small) as compared with the case of forming an image on plain paper. For this reason, if the type of paper is thick paper, the opening / closing amount and opening / closing cycle of the blowing port 32 by the blowing port opening / closing mechanism 33 are changed as compared with the case of plain paper (reducing the opening / closing amount, shortening the opening / closing cycle). Thus, it is possible to increase the cooling efficiency by blowing air intensively to the upper layer portion of the paper stacked on the paper stacking plate 25.

  Subsequently, the paper discharge control unit 37 confirms whether or not the shutter member 36 is in the closed state (fully closed state) based on the detection signal of the shutter opening / closing sensor 44 (step S7), and the shutter member 36 is closed. If it is a state, a raising / lowering control process and a discharge | emission control process are performed (step S8). The detection signal of the shutter open / close sensor 44 is, for example, in an on state when the shutter member 36 completely closes the air blowing port 32 and is in an off state otherwise. Therefore, the paper discharge control unit 37 determines that the shutter member 36 is in the closed state if the detection signal of the shutter open / close sensor 44 is on, and the shutter is detected if the detection signal of the shutter open / close sensor 44 is off. It is determined that the member 36 is not closed.

  FIG. 12 is a flowchart showing the procedure of the elevation control process. First, the paper discharge control unit 37 checks whether or not the height of the paper stacked on the paper stacking plate 25 (paper stacking height) has reached a predetermined height (step S11). If the predetermined height has been reached, the elevation drive unit 39 is driven to lower the sheet stacking plate 25 by a predetermined amount as shown in FIG. 13 (step S12). The sheet stacking height refers to the height of the top surface of the sheets stacked on the sheet stacking plate 25. Whether the paper stacking height has reached a predetermined height may be determined based on, for example, a detection signal of a sensor (paper height detection sensor) that detects the paper stacking height.

  In this processing example, every time the sheet stacking height reaches a predetermined height, the sheet stacking plate 25 is lowered by a predetermined amount. Each time a predetermined number of sheets are discharged, the paper stacking plate 25 may be lowered by a predetermined amount.

  FIG. 14 is a flowchart of the procedure of the discharge control process. First, the paper discharge control unit 37 checks whether or not the paper discharge roll 24 is discharging paper (paper is being discharged) based on the detection signal of the paper discharge detection sensor 43 (step S21). If the paper is being discharged, the process is directly terminated. If the paper is not being discharged, the driving of the opening / closing drive unit 42 is stopped and the shutter opening / closing operation is temporarily stopped (step S22).

  Next, the paper discharge control unit 37 drives the retracting drive unit 41 to move the claw 34 from the protruding position to the retracted position (step S23). As a result, as shown in FIGS. 15A and 15B, when the blower port 32 is completely closed by the shutter member 36, the paper 27 that has been on the protruding nail 34 retracts the nail 34. At the same time, it falls by its own weight and is loaded on the sheet stacking plate 25.

  Next, the paper discharge control unit 37 checks whether or not a predetermined time has elapsed (step S24). The predetermined time is set according to the time required for the paper ejected by the paper discharge roll 24 and placed on each claw 34 to drop onto the paper stacking plate 25 after the claw 34 is retracted. It is what is done.

  When the predetermined time has elapsed, the paper discharge control unit 37 confirms whether or not the paper discharge roll 24 is discharging the next paper (paper is being discharged) based on the detection signal of the paper discharge detection sensor 43 ( Step S25). If the next sheet is not being discharged, the retracting drive unit 41 is driven to move the claw 34 from the retracted position to the projecting position. The drive unit 41 is driven to move the claw 34 from the retracted position to the protruding position (step S26). The next sheet described here refers to a sheet discharged after the sheet determined to be discharged in step S21. Thereafter, the paper discharge control unit 37 drives the opening / closing drive unit 42 to restart the shutter opening / closing operation (step S27).

  FIG. 16 is a timing chart of the shutter opening / closing operation, the paper discharging operation, and the claw retracting operation. In the figure, time T1 corresponds to the predetermined time applied in step S24. The time T2 is the shortest time for the shutter member 36 to keep the air blowing port 32 in a completely closed state when the shutter member 36 is repeatedly moved up and down to open and close the air blowing port 32. The period during paper discharge depends on the length of the paper, and the period during non-paper discharge depends on the paper interval.

  First, in the first case, when the air blowing port 32 is completely closed by the shutter member 36, the paper is not being discharged, so the claw 34 is moved to the retracted position at that stage. After that, when the time T1 has elapsed since the blower port 32 is completely closed by the shutter member 36, the paper is not being discharged, and the claw 34 is moved to the protruding position at that stage. Thereafter, due to the relationship of time T1 <T2, the shutter member 36 is switched to the open state when the time T2 has elapsed after the air blowing port 32 is completely closed by the shutter member 36.

  In the second case, when the blower port 32 is completely closed by the shutter member 36, the paper is not being discharged, so the claw 34 is moved to the retracted position at that stage. After that, when the time T1 has elapsed since the air outlet 32 is completely closed by the shutter member 36, the sheet is being discharged, and the discharged state continues even after the time T2. At the stage of switching from paper discharge to non-paper discharge, the claw 34 is moved to the protruding position and the shutter member 36 is switched to the open state.

  In the third case, when the blower port 32 is completely closed by the shutter member 36, the paper is being discharged, so the claw 34 is moved to the retracted position when switching from discharging to non-discharge. Has moved. After that, since the air outlet 32 is completely closed by the shutter member 36 and the time T1 has elapsed, the paper is not being discharged, so the claw 34 is moved to the protruding position and the shutter member 36 is switched to the open state. ing.

  In the above embodiment, the operation start timing of the blower 31 and the blower opening / closing mechanism 33 is controlled on the basis of the number of discharged sheets or the elapsed time from the start of discharging, but the present invention is not limited to this. The operation of the blower 31 and the blower opening / closing mechanism 33 may be started simultaneously with the start of paper discharge. In that case, the air blowing amount of the blower 31 is set to be weaker than the normal amount until the number of discharged sheets from the start of discharging reaches the predetermined number or until the elapsed time from the start of discharging reaches the predetermined time. Assuming that the amount of air blown by the blower 31 is increased to a normal amount when the number of paper discharged from the start of paper discharge reaches a predetermined number or when the elapsed time from the start of paper discharge reaches a predetermined time. Also good.

  In the above-described embodiment, the paper discharge roll 24 is provided in the paper discharge device 3. However, the paper discharge roll 24 may be provided in the image forming apparatus main body 2.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus to which the present invention is applied. 3 is a plan view illustrating a configuration example of a paper discharge device. FIG. It is C arrow line view of FIG. FIG. 3 is a view taken in the direction of arrow D in FIG. 2. It is a figure explaining the movement position of a nail | claw. It is the schematic which shows the structural example of a ventilation opening / closing mechanism. 3 is a block diagram illustrating a configuration example of a control system that controls the operation of the paper discharge device. FIG. 6 is a flowchart illustrating a procedure of paper discharge processing. It is a top view which shows the operation example of an air blower. It is a figure which shows the mode of shutter opening / closing operation | movement. It is a figure which shows the floating state of a paper. It is a flowchart which shows the procedure of a raising / lowering control process. FIG. 10 is a diagram illustrating an example of the lifting / lowering operation of a sheet stacking plate. It is a flowchart for the procedure of the discharge control process. It is a figure which shows a state change when a nail | claw is moved from a protrusion position to a retracted position. 6 is a timing chart of a shutter opening / closing operation, a paper discharge operation, and a claw retracting operation.

Explanation of symbols

  24 ... paper discharge roll, 25 ... paper stacking plate, 27 ... paper, 31 ... air blower, 32 ... air blow opening, 33 ... air blow opening / closing mechanism, 34 ... claw, 36 ... shutter member, 37 ... paper discharge control unit

Claims (8)

  1. A paper stacking means for storing the discharged paper in a stacked state;
    An air blowing means for blowing air through an air blowing port to an end portion of the paper loaded on the paper loading means;
    A paper discharge device comprising: a blower opening / closing unit that opens and closes the blower opening in a paper stacking direction.
  2. The paper discharge apparatus according to claim 1, further comprising: a restriction unit that restricts a maximum height of the sheet floated by blowing air from the air blowing unit at a position lower than a paper discharge height.
  3. A plurality of the air blowing means are provided at different positions in the paper discharge direction,
    The paper discharge device according to claim 1, wherein the plurality of air blowing units are selectively operated according to a length of paper to be discharged.
  4. The paper discharge device according to claim 1, further comprising means for controlling the start timing of the air blowing operation of the air blowing means based on the number of paper discharged or the elapsed time from the start of paper discharge.
  5. The paper discharge device according to claim 1, further comprising means for variably controlling the start timing of the air blowing operation of the air blowing means according to the type of paper.
  6. The paper discharge device according to claim 1, further comprising: a unit that variably controls the amount of air blown by the air blowing unit according to the type of paper.
  7. Image forming means for forming an image on paper;
    Paper discharge means for discharging the paper on which the image is formed by the image forming means;
    A paper stacking means for storing the paper discharged by the paper discharge means in a stacked state;
    An air blowing means for blowing air through an air blowing port to an end portion of the paper loaded on the paper loading means;
    An image forming apparatus comprising: a blowing port opening / closing unit that opens and closes the blowing port in a sheet stacking direction.
  8. The image forming apparatus according to claim 7, wherein whether or not to operate the blowing unit and the blowing port opening / closing unit is switched according to image information formed on the sheet by the image forming unit.
JP2006202757A 2006-07-26 2006-07-26 Paper discharge device and image forming apparatus Expired - Fee Related JP4862531B2 (en)

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JP2010076934A (en) * 2008-08-29 2010-04-08 Kyocera Mita Corp Discharging device and image forming device
JP2011051676A (en) * 2009-08-31 2011-03-17 Ricoh Co Ltd Sheet loading device and image forming device
JP2014065609A (en) * 2012-09-05 2014-04-17 Ricoh Co Ltd Paper processing device, image forming system, and paper processing method
WO2015025627A1 (en) * 2013-08-23 2015-02-26 富士フイルム株式会社 Sheet stacking device

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CN104192618A (en) * 2014-08-26 2014-12-10 苏州新协力机器制造有限公司 Plate output mechanism

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JP2000153948A (en) * 1998-11-19 2000-06-06 Tohoku Ricoh Co Ltd Sheet discharge board
JP2000318246A (en) * 1999-05-14 2000-11-21 Tohoku Ricoh Co Ltd Printing apparatus
JP2001242769A (en) * 2000-02-25 2001-09-07 Canon Inc Image forming device

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JPH0616304A (en) * 1992-06-29 1994-01-25 Nisca Corp Paper housing device
JP2000153948A (en) * 1998-11-19 2000-06-06 Tohoku Ricoh Co Ltd Sheet discharge board
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JP2010076934A (en) * 2008-08-29 2010-04-08 Kyocera Mita Corp Discharging device and image forming device
JP2011051676A (en) * 2009-08-31 2011-03-17 Ricoh Co Ltd Sheet loading device and image forming device
JP2014065609A (en) * 2012-09-05 2014-04-17 Ricoh Co Ltd Paper processing device, image forming system, and paper processing method
WO2015025627A1 (en) * 2013-08-23 2015-02-26 富士フイルム株式会社 Sheet stacking device
JP5940734B2 (en) * 2013-08-23 2016-06-29 富士フイルム株式会社 Paper stacking device
US9630794B2 (en) 2013-08-23 2017-04-25 Fujifilm Corporation Sheet stacking device

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